Anti Aldol reactions of α-alkoxymethyl ketones: Application to the total synthesis of (+)-restricticin
作者:Ian Paterson、Thorsten Nowak
DOI:10.1016/0040-4039(96)01879-5
日期:1996.11
The antifungal agent (+)-restricticin (1) was prepared in 12 steps from ketone (S)-8. The key steps are (i) the boron-mediated anti aldolreaction of (S)-8 with 9 to give 13 and (ii) the cyclisation reaction 4 → 15.
The highly enantioselective organocatalyticRobinsonannulation of α,β-unsaturatedaldehydes was achieved, catalyzed by l-proline and trialkylamines and providing the formal [4 + 2] cycloaddition adducts. Additionally, in some examples in the catalysis with diarylpyrrolinol silyl ethers, the reactions afforded the [4 + 2] adducts with high enantioselectivity (>99.5% ee). The structure of the adduct
Enantioselective Total Synthesis of (+)-Eupenoxide and (+)-Phomoxide: Revision of Structures and Assignment of Absolute Configuration
作者:Goverdhan Mehta、Subhrangsu Roy
DOI:10.1021/ol0492288
日期:2004.7.1
[reaction: see text] Stereo- and enantioselective total syntheses of the novel, polyketide natural products ent-eupenoxide and ent-phomoxide have been accomplished from the readily available Diels-Alder adduct of cyclopentadiene and p-benzoquinone. These synthetic studies necessitate the revision of the assigned stereostructures of the natural products and reveal their absolute configuration.
Restrictinol 2 and 9, 10, 11, 12-tetrahydro-7-desmethylrestricticin (Ro 09-1571) have been synthesized from L-glucose. Ro 09-1571 showed improved in vitro antifungal activity and chemical stability as compared with Restricticin 1.